Degradable iron-rich mesoporous dopamine as a dual-glutathione depletion nanoplatform for photothermal-enhanced ferroptosis and chemodynamic therapy.

Glutathione (GSH) is a crucial factor in limiting the effects of chemodynamic therapy (CDT) and ferroptosis, an iron-based cell death pathway. Based on this, we constructed iron-rich mesoporous dopamine (MPDA@Fe) nanovehicles with a dual-GSH depletion function by combining MPDA and Fe. Poly (ethylene glycol) (PEG) was further modified to provide desirable stability (PM@Fe) and glucose oxidase (GOx) was grafted onto PM@Fe (GPM@Fe) to address the limitation of hydrogen peroxide (H2O2). After the nanoparticles reached the tumor site, the weakly acidic microenvironment promoted the release of Fe. Then FeII reacted with H2O2 to generate hydroxyl radical (OH) and FeIII. The generated FeIII was reduced to FeII by GSH, which circularly participated in the Fenton reaction and continuously produced tumor inhibitory free radicals. Meanwhile, GOx consumed glucose to provide H2O2 for the reaction. MPDA had also been reported to deplete GSH. Therefore, dual consumption of GSH led to the destruction of intracellular redox balance and inhibition of glutathione-dependent peroxidase 4 (GPX4) expression, resulting in an increase in lipid peroxides (LPO) and further induction of ferroptosis. Additionally, MPDA-mediated photothermal therapy (PTT) raised the temperature of tumor area and produced photothermal-enhanced cascade effects. Hence, the synergistic strategy that combined dual-GSH depletion-induced ferroptosis, enhanced CDT and photothermal cascade enhancement based on MPDA@Fe could provide more directions for designing nanomedicines for cancer treatment.